“…16 It is generally believed that V Cd is an acceptor, the main responsible for the p-type conductivity of the as-grown material, whereas Te Cd is a donor; however, there has been much discussion about their geometry and the position of the respective defect levels. Back to the 1990s, electron paramagnetic resonance ͑EPR͒ spectroscopy and electron-nuclear double resonance have found two centers which have originally been related to the Te vacancy ͑F center͒ [17][18][19] and the Cd vacancy. 18,20 The former, an isotropic center with an ionization energy of 0.2 eV, has subsequently been assigned to Te Cd + ͑Ref.…”